Matching Items (54)

128500-Thumbnail Image.png

Temporal assessment of nanoparticle accumulation after experimental brain injury: Effect of particle size

Description

Nanoparticle (NP) based therapeutic and theranostic agents have been developed for various diseases, yet application to neural disease/injury is restricted by the blood-brain-barrier (BBB). Traumatic brain injury (TBI) results in

Nanoparticle (NP) based therapeutic and theranostic agents have been developed for various diseases, yet application to neural disease/injury is restricted by the blood-brain-barrier (BBB). Traumatic brain injury (TBI) results in a host of pathological alterations, including transient breakdown of the BBB, thus opening a window for NP delivery to the injured brain tissue. This study focused on investigating the spatiotemporal accumulation of different sized NPs after TBI. Specifically, animal cohorts sustaining a controlled cortical impact injury received an intravenous injection of PEGylated NP cocktail (20, 40, 100, and 500 nm, each with a unique fluorophore) immediately (0 h), 2 h, 5 h, 12 h, or 23 h after injury. NPs were allowed to circulate for 1 h before perfusion and brain harvest. Confocal microscopy demonstrated peak NP accumulation within the injury penumbra 1 h post-injury. An inverse relationship was found between NP size and their continued accumulation within the penumbra. NP accumulation preferentially occurred in the primary motor and somatosensory areas of the injury penumbra as compared to the parietal association and visual area. Thus, we characterized the accumulation of particles up to 500 nm at different times acutely after injury, indicating the potential of NP-based TBI theranostics in the acute period after injury.

Contributors

Created

Date Created
  • 2016-07-22

128415-Thumbnail Image.png

Endogenous Repair Signaling after Brain Injury and Complementary Bioengineering Approaches to Enhance Neural Regeneration

Description

Traumatic brain injury (TBI) affects 5.3 million Americans annually. Despite the many long-term deficits associated with TBI, there currently are no clinically available therapies that directly address the underlying pathologies

Traumatic brain injury (TBI) affects 5.3 million Americans annually. Despite the many long-term deficits associated with TBI, there currently are no clinically available therapies that directly address the underlying pathologies contributing to these deficits. Preclinical studies have investigated various therapeutic approaches for TBI: two such approaches are stem cell transplantation and delivery of bioactive factors to mitigate the biochemical insult affiliated with TBI. However, success with either of these approaches has been limited largely due to the complexity of the injury microenvironment. As such, this review outlines the many factors of the injury microenvironment that mediate endogenous neural regeneration after TBI and the corresponding bioengineering approaches that harness these inherent signaling mechanisms to further amplify regenerative efforts.

Contributors

Agent

Created

Date Created
  • 2015-05-12

Optimizing Recombinant Protein Production for Domain Antibodies: Proof-of-Concept

Description

Recent studies in traumatic brain injury (TBI) have found a temporal window where therapeutics on the nanometer scale can cross the blood-brain barrier and enter the parenchyma. Developing protein-based therapeutics

Recent studies in traumatic brain injury (TBI) have found a temporal window where therapeutics on the nanometer scale can cross the blood-brain barrier and enter the parenchyma. Developing protein-based therapeutics is attractive for a number of reasons, yet, the production pipeline for high yield and consistent bioactive recombinant proteins remains a major obstacle. Previous studies for recombinant protein production has utilized gram-negative hosts such as Escherichia coli (E. coli) due to its well-established genetics and fast growth for recombinant protein production. However, using gram-negative hosts require lysis that calls for additional optimization and also introduces endotoxins and proteases that contribute to protein degradation. This project directly addressed this issue and evaluated the potential to use a gram-positive host such as Brevibacillus choshinensis (Brevi) which does not require lysis as the proteins are expressed directly into the supernatant. This host was utilized to produce variants of Stock 11 (S11) protein as a proof-of-concept towards this methodology. Variants of S11 were synthesized using different restriction enzymes which will alter the location of protein tags that may affect production or purification. Factors such as incubation time, incubation temperature, and media were optimized for each variant of S11 using a robust design of experiments. All variants of S11 were grown using optimized parameters prior to purification via affinity chromatography. Results showed the efficiency of using Brevi as a potential host for domain antibody production in the Stabenfeldt lab. Future aims will focus on troubleshooting the purification process to optimize the protein production pipeline.

Contributors

Agent

Created

Date Created
  • 2019-05

134521-Thumbnail Image.png

Characterization of Inflammatory Cell Population in Brain After SDF-1α Injection

Description

The brain is the most important part of the central nervous system in the human body. It is the center of consciousness and controls all voluntary motor activity of the

The brain is the most important part of the central nervous system in the human body. It is the center of consciousness and controls all voluntary motor activity of the body. Mechanical trauma sustained to the head during a car accident, fall, or sports injury can lead to a traumatic brain injury (TBI) that may have long ranging and sustained physical, cognitive and emotional effects. TBI is the most common form of brain injury and it contributes to one third of all injury related deaths in the United States. The Stabenfeldt lab aims to develop regenerative strategies that will harness inherent endogenous repair mechanisms in traumatic brain injury to improve functional outcomes in cognitive and motor functions. Previous research has demonstrated that the acute inflammatory response after TBI releases soluble cytokines that mediate regeneration after TBI. One of such soluble signal is stromal cell derived factor-1α (SDF-1α) and its receptor CXCR4. The SDF-1α/CXCR4 signaling axis directs the migration and organization of neural progenitor/ stem cells which is important in the regeneration of the injury area. In this study, we probed this paradigm by injecting bolus and nanoparticle exogenous SDF-1α intracortically into mice then sacrificing at 1, 3, and 7 days’ post-injection. Increased CXCR4 positive cells were expressed around the SDF-1α injection area. This study specifically focused on characterizing microglia and macrophage population in the brains that expressed CXCR4 via immunohistochemistry. Data from this study showed that the bolus group initiated microglial activation within the injection tract particularly at day 3 post injection which was resolved by day 7. However, the nanoparticle group initiated the activation of microglial/macrophages as early as day 1 post injection which proceeded to day 7. This shows that the nanoparticle groups initiated an
3
inflammatory reaction in the injection tract irrespective of SDF-1α since the blank nanoparticle (nanoparticle with no SDF-1α) group exhibited the identical trend.

Contributors

Agent

Created

Date Created
  • 2017-05

133955-Thumbnail Image.png

Pelvic Ultrasound to Evaluate Parameters that may Affect Intrauterine Device (IUD) Placement Failure and Success

Description

Intrauterine devices (IUDs) have become one of the most common types of contraception in the United States. In the last decade, the American College of Obstetricians and Gynecologists, the World

Intrauterine devices (IUDs) have become one of the most common types of contraception in the United States. In the last decade, the American College of Obstetricians and Gynecologists, the World Health Organization, and the Food and Drug Administration (FDA) updated IUD recommendations to include placement in younger populations and nulliparous women. Research has shown that younger, nulliparous women may have smaller uterine dimensions and it is possible that larger IUDs are not suitable for those populations. This study retrospectively evaluated follow-up pelvic ultrasounds showing uterine dimensions and IUD positions of 57 women who had IUDs placed in a clinic. The largest IUD, the Paragard, showed a significantly higher rate of malpositioning than the Kyleena, Liletta, and Mirena IUDs. There is concern that the Paragard IUD, which is most commonly malpositioned, is also the IUD most dependent on position for adequate contraception. There was no correlation between uterine dimensions and IUD position at the time of analysis, however. Further data collection will continue in hopes that a larger sample size will reveal a parameter which affects IUD placement. Should further data analysis show that uterine width plays an important role in IUD position, the design for a device which can measure the width of patient's uterus (without the need for pelvic ultrasound) has been included. The concept generation for this measurement device includes laser measurements of uterine cavity width at different known lengths from the fundal wall, which output to an LED screen for recording.

Contributors

Agent

Created

Date Created
  • 2018-05

Human Neural Progenitor Cell Adhesion on PDMS Substrates

Description

Abstract
The aim of the research performed was to increase research potential in the field of cell stimulation by developing a method to adhere human neural progenitor cells (hNPC’s) to

Abstract
The aim of the research performed was to increase research potential in the field of cell stimulation by developing a method to adhere human neural progenitor cells (hNPC’s) to a sterilized stretchable microelectrode array (SMEA). The two primary objectives of our research were to develop methods of sterilizing the polydimethylsiloxane (PDMS) substrate being used for the SMEA, and to derive a functional procedure for adhering hNPC’s to the PDMS. The proven method of sterilization was to plasma treat the sample and then soak it in 70% ethanol for one hour. The most successful method for cell adhesion was plasma treating the PDMS, followed by treating the surface of the PDMS with 0.01 mg/mL poly-l-lysine (PLL) and 3 µg/cm2 laminin. The development of these methods was an iterative process; as the methods were tested, any problems found with the method were corrected for the next round of testing until a final method was confirmed. Moving forward, the findings will allow for cell behavior to be researched in a unique fashion to better understand the response of adherent cells to physical stimulation by measuring changes in their electrical activity.

Contributors

Agent

Created

Date Created
  • 2016-05

135280-Thumbnail Image.png

Heart Rate Variability and Electrocardiography in Evaluating Stress

Description

Chronic stress has been linked as a probable contributor to a number of health problems that plague the world today. Obesity, cardiovascular disease, depression, and osteoporosis are all common health

Chronic stress has been linked as a probable contributor to a number of health problems that plague the world today. Obesity, cardiovascular disease, depression, and osteoporosis are all common health risks believed to be exacerbated by stress. While it is nether realistic nor desirable to completely eliminate stress in an individual, proper stress management is important to a healthy lifestyle. Homeostasis is the primary mechanism by which stress, and the stress response, should be analyzed. Environmental factors known as stressors elicit responses from the body, which can be measured in terms of duration and magnitude. These two factors determine the homeostatic response from the body. This thesis proposes the study of heart rate variability (HRV) to measure the response of the autonomic nervous system through time domain analysis (the length of interbeat intervals) and frequency domain analysis (the differences between the lengths of consecutive interbeat intervals). Even with many possible problems, this data still represents valuable proof of concept that HRV analysis may be of use in identifying stress.

Contributors

Agent

Created

Date Created
  • 2012-05

133254-Thumbnail Image.png

Identifying Novel Nanobodies for Traumatic Brain Injury Therapeutics

Description

Traumatic brain injury (TBI) is a serious health problem around the world with few available treatments. TBI pathology can be divided into two phases: the primary insult and the secondary

Traumatic brain injury (TBI) is a serious health problem around the world with few available treatments. TBI pathology can be divided into two phases: the primary insult and the secondary injury. The primary insult results from the bump or blow to the head that causes the initial injury. Secondary injury lasts from hours to months after the initial injury and worsens the primary insult, creating a greater area of tissue damage and cell death. Many current treatments focus on lessening the severity of secondary injury. Secondary injury results from the cyclical nature of tissue damage. Inflammatory pathways cause damage to tissue, which in turn reinforces inflammation. Since many inflammatory pathways are interconnected, targeting individual products within these pathways is impractical. A target at the beginning of the pathway, such as a receptor, must be chosen to break the cycle. This project aims to identify novel nanobodies that could temporarily inactivate the CD36 receptor, which is a receptor found on many immune and endothelial cells. CD36 initiates and perpetuates the immune system's inflammatory responses. By inactivating this receptor temporarily, inflammation and immune cell entry could be lessened, and therefore secondary injury could be attenuated. This project utilized phage display as a method of nanobody selection. The specific phage library utilized in this experiment consists of human heavy chain (V_H) segments, also known as domain antibodies (dAbs), displayed on M13 filamentous bacteriophage. Phage display mimics the process of immune selection. The target is bound to a well as a means of displaying it to the phage. The phage library is then incubated with the target to allow antibodies to bind. After, the well is washed thoroughly to detach any phage that are not strongly bound. The remaining phage are then amplified in bacteria and run again through the same assay to select for mutations that resulted in higher affinity binding. This process, called biopanning, was performed three times for this project. After biopanning, the library was sequenced using Next Generation sequencing (NGS). This platform enables the entire library to be sequenced, as opposed to traditional Sanger sequencing, which can only sequence single select clones at a time thereby limiting population sampling. This type of genetic sequencing allows trends in the complementarity determining regions (CDRs) of the domain antibody library to be analyzed, using bioinformatics programs such as RStudio, FastAptamer, and Swiss Model. Ultimately, two nanobody candidates were identified for the CD36 receptor.

Contributors

Agent

Created

Date Created
  • 2018-05

137180-Thumbnail Image.png

Utilization of Nanoparticles for Identifying Fibrin Deposition in Neural Tissue

Description

The main objective of this research is to develop and characterize a targeted contrast agent that will recognize acute neural injury pathology (i.e. fibrin) after traumatic brain injury (TBI). Single

The main objective of this research is to develop and characterize a targeted contrast agent that will recognize acute neural injury pathology (i.e. fibrin) after traumatic brain injury (TBI). Single chain fragment variable antibodies (scFv) that bind specifically to fibrin have been produced and purified. DSPE-PEG micelles have been produced and the scFv has been conjugated to the surface of the micelles; this nanoparticle system will be used to overcome limitations in diagnosing TBI. The binding and imaging properties will be analyzed in the future to determine functionality of the nanoparticle system in vivo.

Contributors

Agent

Created

Date Created
  • 2014-05

148068-Thumbnail Image.png

Characterization of Hyaluronic Acid Shear Thinning Hydrogels Towards Neural Cell Applications

Description

Traumatic brain injury (TBI) is a widespread health issue that affects approximately 1.7 million lives per year. The effects of TBI go past the incident of primary injury, as chronic

Traumatic brain injury (TBI) is a widespread health issue that affects approximately 1.7 million lives per year. The effects of TBI go past the incident of primary injury, as chronic damage can follow for years and cause irreversible neurodegeneration. A potential strategy for repair that has been studied is cell transplantation, as neural stem cells improve neurological function. While promising, neural stem cell transplantation presents challenges due to a relatively low survival rate post-implantation and issues with determining the optimal method of transplantation. Shear-thinning hydrogels are a type of hydrogel whose linkages break when under shear stress, exhibiting viscous flow, but reform and recover upon relaxation. Such properties allow them to be easily injected for minimally invasive delivery, while also shielding encapsulated cells from high shear forces, which would normally degrade the function and viability of such cells. As such, it is salient to research whether shear-thinning hydrogels are feasible candidates in neural cell transplantation applications for neuroregenerative medicine. In this honors thesis, shear-thinning hydrogels were formed through guest-host interactions of adamantane modified HA (guest ad-HA) and beta-cyclodextrin modified HA (host CD-HA). The purpose of the study was to characterize the injection force profile of different weight percentages of the HA shear-thinning hydrogel. The break force and average glide force were also compared between the differing weight percentages. By understanding the force exerted on the hydrogel when being injected, we could characterize how neural cells may respond to encapsulation and injection within HA shear-thinning hydrogels. We identified that 5% weight HA hydrogel required greater injection force than 4% weight HA hydrogel to be fully delivered. Such contexts are valuable, as this implies that higher weight percentage gels impart higher shear forces on encapsulated cells than lower weight gels. Further study is required to optimize our injection force system’s sensitivity and to investigate if cell encapsulation increases the force required for injection.

Contributors

Agent

Created

Date Created
  • 2021-05